﻿using System;

class CalculateNxK

            // Write a program that calculates N!*K! / (K-N)! for given N and K (1<N<K).

{
    static void Main()
    {
        Console.WriteLine("Enter values for 'N' and 'K' such that 1<N<K");
        double n = double.Parse(Console.ReadLine());
        double k = double.Parse(Console.ReadLine());
        double factN = 1;
        double factK = 1;
        double factBoth = 1;
        for (ulong i = 1; i <= n; i++)
        {
             factN *= i;
        }
        for (ulong i = 1; i <= k; i++)
        {
            factK *= i;
        }
        for (ulong i = 1; i <= k - n; i++)
        {
            factBoth *= i;
        }
        Console.WriteLine("The result of N!*K!/(K-N)! is: " + ((factN * factK) / factBoth));
    }
}

